Examples of known molding systems are (amongst others): (i) the HyPET™ Molding System, (ii) the Quadloc™ Molding System, (iii) the Hylectric™ Molding System, and (iv) the HyMet™ Molding System, all manufactured by Husky Injection Molding Systems Limited (Location: Bolton, Ontario, Canada).
U.S. Pat. No. 5,182,118 (Inventor: Hehl; Published: 1993 Jan. 26) discloses a plasticising unit for injection molding machine that has two part barrel design where joint line between them always lies in low pressure zone behind non-return valve at front of screw. More specifically, this patent discloses that in the plasticizing cylinder the plasticized plastic material is transported by a rotating feed screw into a space which is in front of the feed screw and the plastic material is subsequently injected into the injection mold of the injection molding machine by an axial discharge stroke of the feed screw. During that stroke a backflow-preventing valve is effective to seal a high-pressure space from a low-pressure space, which contains the feed screw. The plasticizing cylinder is composed of a cylinder head, which always completely encloses the high-pressure space and the backflow-preventing valve, and a cylinder shank, which encloses the low-pressure space and the feed screw. Even when the feed screw is in its rearmost initial position will the high-pressure space not be adjoined by a joint which leads to the outside of the plasticizing cylinder so that the problems previously encountered in connection with the sealing of the high-pressure space are avoided.
World Intellectual Property Organization Patent Number WO 9500312 (Inventor: WOLFF; Published: 1995 Jan. 5) discloses a hot runner distributor for supplying molten thermoplastic materials to hot nozzles at molding tools that has pipe plug-type connections that allow thermal expansion. Each pipe plug-type connection has two mutually aligned pipe ends which surround the runner of molten material and are mutually separated by an expandable joint. Both pipe ends are enclosed in the area of the expandable joint by a common cooling ring. The molten plastic material which solidifies under the action of the cooling ring seals the pipe plug-type connection in the area of the expandable joint.
U.S. Pat. No. 6,942,006 (Inventor: KONO; Published: 13 Sep. 2005) discloses a metal injection molding apparatus with features which reduce the amount of metal which enters a drive mechanism of the apparatus. The apparatus contains an injection chamber having an accumulation portion and a shaft housing portion. The shaft housing may extend all the way to the position of an injection member in a fully retracted position. The accumulation portion and the shaft housing may comprise different vessels attached to each other with an insulating gasket provided therebetween. The insulator material of the gasket is preferably made of asbestos, a heat insulating ceramic or any other suitable heat resistant material. The material to be injected, such as a liquid or thixotropic metal, enters the injection chamber through an entry opening configured in the accumulation portion, and exits the accumulation portion, when injected, through a nozzle aperture configured at an end of the accumulation portion and into the mold. The shaft housing portion may include openings in the sidewalls through which any melt leakage past from the injection member that has not been caught by a series of piston rings may egress. Accordingly, the shaft housing, and gasket, is not configured to experience pressurized melt of molding material.
U.S. published patent application No. 2005/0255189 (Inventor: MANDA, Jan; et al; Published: 17 Nov. 2005) discloses a cooled connection between melt conduits of a runner system to form a seal of at least partially solidified molding material (a metallic molding material). Discloses is a seal in the metal molding system, such as those between melt conduit components of a barrel assembly and a runner system. U.S. Pat. No. 2005/0255189 discloses a cooled interface for providing a seal of at least partially solidified molding material between the components of the runner system. A problem with the cooled interface may occur when the amount of heat required to be removed to effect the seal of at least partially solidified molding material is also sufficient to over-cool an adjacent portion of a melt passageway and cause a plug of at least partially solidified molding material to form therein which may affect the proper flow of the molding material therethrough. Others have relied on face seals across a clamped interface between mating faces of adjacent melt conduits. In practice, the mating faces of the melt conduits that form the interface do not adequately conform to one another to affect a reliable seal against the leakage of the generally low viscosity molding material under the injection pressure.